Fig. 8. (a) Bisignated CD signals observed at the surface plasmon frequency with positive and negative couplets for NP bunches adsorbed on the surface of d- and l-diphenylalanine nanotubes. (b and c) TEM images of diphenylalanine peptide nanotubes (b) in the presence of Au NP seeds and (c) after photochemical irradiation for 3 h in the presence of HAuCl4 for reductive growth of NPs on the seeds. The inset shows the HRTEM image of one of the NP bunches. Adapted with permission from ref. 101. Copyright 2010 American Chemical Society. (d) Schematic illustration of plasmonic CD induction by chiral riboflavin molecules in the vicinity of gold islands deposited on a glass substrate. Chiral molecules induce optical activity in Au islands leading to CD signals at the metal plasmon resonance of 570 nm. Adapted with permission from ref. 107. Copyright 2013 American Chemical Society. (e) CD and UV-vis spectra of Au–(DNA–Ag)–Au trimers, and control experiments. The inset shows a TEM image and a scheme of the core–shell trimer nanostructure. Reproduced with permission from ref. 109. Copyright 2015 Wiley VCH.
